Sun Fire[TM] V1280/E2900/3800/48x0/E4900/6800/E6900: Prtdiag and showboard display wrong cpu speed.

Asset ID:	1-72-1006508.1
Update Date:	2010-07-06
Keywords:

Solution Type Problem Resolution Sure

Solution 1006508.1 : Sun Fire[TM] V1280/E2900/3800/48x0/E4900/6800/E6900: Prtdiag and showboard display wrong cpu speed.

Related Items


Sun Fire E6900 Server
 Sun Fire 3800 Server
 Sun Fire 6800 Server
 Sun Fire E4900 Server
 Sun Fire 4800 Server
 Sun Fire V1280 Server
 Sun Fire E2900 Server
 Sun Fire 4810 Server

Related Categories


GCS>Sun Microsystems>Servers>Midrange V and Netra Servers
 GCS>Sun Microsystems>Servers>Midrange Servers

PreviouslyPublishedAs
209106

Symptoms
Prtdiag and showboard display wrong cpu speed on a Sun Fire[TM] Serengeti domain:

---------------------------
Output from showboard:
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/N0/SB4/P0 2.1 UltraSPARC-IV+, 1500MHz, 32M ECache
/N0/SB4/P1 2.1 UltraSPARC-IV+, 1510MHz, 32M ECache
/N0/SB4/P2 2.1 UltraSPARC-IV+, 1500MHz, 32M ECache
/N0/SB4/P3 2.1 UltraSPARC-IV+, 1500MHz, 32M ECache

---------------------------
System Controller (SC) log:
---------------------------
System frequency of 151 MHz is outside of tolerance: Expected range: 149.5 MHz to 150.5 Mhz.
System frequency of 151 MHz is outside of tolerance: Expected range: 149.5 MHz to 150.5 Mhz.

Resolution
During POST, platform system clock sets the CPU speeds on a 'per-CPU' basis. The system clock is provided by the MAIN SC. If system clock, for some reason, is skewed out of tolerance, an incorrect CPU speed will be programmed.

The data might seem to indicate that the CPU is defective, so replacing the System Board might seem to be the correct action. In fact, root cause is the system clock source, the MAIN SC.

Follow the instructions in the Temporary Workaround section of this article to resolve this issue.

Relief/Workaround

- CPU speed is set correctly then the former MAIN SC should be replaced.
- CPU speed is set incorrectly implicating the System Board (CPU) as Root Cause.

Please schedule service to replace the faulty hardware by contacting your local Sun Service representative and providing this document ID as a reference.

Additional Information
The log files and data (See Problem Section) indicate that the CPU is Root Cause to this event, perhaps misleading some to think the System Board (CPU) is the prime suspect.

CR 6325921 will change this messaging to indicate the accurate suspect, the SC (Scheduled for ScApp 5.20).

Contact your local Sun Service representative with any questions on this information.

Product
Sun Fire V1280 Server
Sun Fire 4800 Server
Sun Fire 4810 Server
Sun Fire 6800 Server
Sun Fire E2900 Server
Sun Fire E4900 Server
Sun Fire E6900 Server
Sun Fire 3800 Server

Internal Comments
The system clock is derived from two clock sources on the System controllerand an average is derived from both clocks. This clock average is then being tested twice during post and the value sampled will be used as CPU speed.

To test this, contact PTS to get assistance to understand and run

the following

Unit Test

---------

0. To verify: print ScSbbcAsic.getInstance().getSystemFrequency()

1. check current configured speed (75MHz).

2. Use clock and change to synthesizer

3. Use margin clock and change the clock speed

4. Use the spare SC and change its clock

To inject an error

1. Use print ScEpld.setTClock(<value>)

- Depending on the value, a different frequency is used and the warning

message will occur.

As the message indicates a CPU failure, you might be tempted to replace the

System board. This is not the correct action.

Corrective action is to fail over to the other system controller and replace

the previous main System controller. This is true until ScApp version

5.20.0 is released. When that is released, an upgrade to this firmware will

resolve the issue CR 6325921.

Clock, System Controller CPU speed
Previously Published As
83099

Change History
Date: 2005-11-17
User Name: 83246
Action: Update Canceled
Comment: *** Restored Published Content *** none
Version: 0
Date: 2005-11-08
User Name: 83246
Action: Update Started
Comment: check
Version: 0
Date: 2005-11-04
User Name: 31620
Action: Approved
Comment: See history for details of this article.

All necessary things in place now.

Andy MacBain

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